The question asks for parameters that differentiate between empty strings and NULL values during data unloading. OPTION C (FIELD_OPTIONALLY_ENCLOSED_BY) allows empty strings to be enclosed in quotes (e.g., ""), making them distinguishable from NULL values which would not be enclosed. OPTION D (EMPTY_FIELD_AS_NULL) when set to FALSE ensures empty fields are treated as empty strings rather than NULLs, preserving the distinction. The community discussion shows 100% consensus on CD, with detailed explanations that FIELD_OPTIONALLY_ENCLOSED_BY enables empty string enclosure and EMPTY_FIELD_AS_NULL controls whether empty fields become NULLs. Other options are less suitable: A (ESCAPE_UNENCLOSED_FIELD) handles escaping, not NULL/empty differentiation; B (REPLACE_INVALID_CHARACTERS) deals with character validation; E (SKIP_BLANK_LINES) skips entire lines, not field-level differentiation.